Fused quartz product and process of producing same



Patented Dec. 7, 1926. I

ELIHU THOMSON.

or SWAMPSCOTT, MASSACHUSETTS, assreuon To GENERAL 'nLEc True COMPANY, A CORPORATION or NEW YORK.

FUSED QUARTZ PRODUCT AND PROCESS OF PRODUCING SAME.

No Drawing.

The present invention relates to production of shaped articles from quartz or silica, and its object is to-produce by a molding process articles having substantially the physical properties of fused quartz.

, Silica is capable of-assuming a variety" of allotropic modifications which are distinguishable by physical properties although they are all chemically identical, each consisting of silicondioxide. In nature silica occurs as crystalline quartz of PEtIlZlClGS into objects of deslred' form, the

various forms, but all of the crystalline quartz varieties are convertible by fusion to a distinct physical modification known particularly as a -fused quartz or quartz glass, Fused quartz is a structureless, vitreous material having a thermal expansion coefficient which is so low as to be substantially negligible. Due to the refractory nature of quartz it is diflicult to produce large or.intricate objects by molding a quartz fusion,

comes a mobile liquid which may be cast, but

' only a viscous mass which rapidly congeals l which has been sub grinding into small-parti- I fifteen per cent and when taken "from a furnace. In accordance with my invention, I have produced crucibles or other molded objects havingv substantially the properties-of fused or vitreous quartz b molding small granules or fragments of used quartz containing only suflicient cementing material to obtain coherence, but without destroying the low 'expansionpropert'y of fused quartz. In carrying out my invention, quartz 'ected to fusion is' broken 'up by crushing or cles. The degree of fineness of the particles depends on the size and nature of the a rti--- The particles may be splinmay comprise a mix- -particles. The fused ale to be made.

tered and angular andture of coarse and fine quartz particles areamount of a suitable, inorganic binder, such as kaolin, feldspar, silicate of soda, a refractory glass, or of suitable mixtures ofthese or other mineral substances, The amount of binder ordinarily should not-exceedten to of a lesser amount. T e mixture preferably is moistened with water, and iifv desired,

' Application filed December 2-8, 1923.

so as the fused quartz never be- 1 body of vitreous quartz.

mixed with a small I referably should "be Serial 110.683.262.

small amount of a temporary binder may be added, as for example, a carbonizable agin any way as under pressure,-

glutinant, such as gum, sugar or starch, to Y dried and baked at a temperature sufliciently high glassy quartz. The resulting objects com-t prising particles of vitreous silica cemented together by the more fusible binder are strong and resistant to temperature changes.

What I claim as new; and desire to secure by Letters Patent ofthe United States, is

1. A molded composition consisting largeof distinct particles of fused. or vitreous quartz per cent of cementing material the thermal expansion coeflicient of the mass as 'a whole being substantially as low as a homogeneous 2. A molded composition consisting of particles of silica'in a vitreous State, and a vitreous material more fusible than silica, distributed between said silica particles in an amount not in excess of about fifteen per cent, the particles of'silica being bound into coherent form by partial fus10n of said hinder, the composition having a thermal to soften the vitreous binder, but' I not so high as to devitrify' the fused quartz,

bound together with, less than ten expansion coeificient substantially no higher than homogeneous fused quartz.

3. The method offabricating articles-having substantially the properties of fused or. vitreous quartz which consists in converting by fusion to a vitreous state crystalline silica, mixing a small proportion of amore' fusible vitreous material therewith, molding the mixture, and finallyheating to a'temperature su'fliciently high to soften the binder but insufficient to fuse saidsilica.

4. The method of fabricating articles 1 from vitreous silica which consistsin commmutmg vitreous sihca into small angular 'particles, adding theretde binder ofmo're cemented together by a Binder of vitreous fusible vitreous material, shaping the mixmaterial having a' lower fusing point than ture to desired form, and firm at a. temsilica.

' perature of about 900 to 1000 to produce In witness whereof, I have hereunto setcoherence. my hand this,24th day of December, 1923.

5. A coherent, shaped article comprising fragments of vitreous silicwof different sizes ELIHU THOMSON. 

